The incident happened Wednesday night in St. Paul, the St. Paul Pioneer Press reported.
Two officers in a squad car the pair of teenagers fighting in the middle of a street and intervened.
The 17-year-old victim said the 14-year-old jumped on his back and assaulted him.
After the suspect was put in the squad car, he told police he was actually trying to rob the victim.
The suspect told police, "I work at Burger King for minimum wage and I'm tired of it."
"The officers were of the impression the victim didn't even know he was being robbed," police watch commander Eric Anderson said.
The 14-year-old was booked into the juvenile detention center on suspicion of robbery.
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